220 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



upon the etchings which may be produced on the crystalline 

 faces of many mineral species. Thus on crystals of calcite 

 minute triangular depressions may be produced by subject- 

 ing them to the working of dilute bydrocholoric acid ; crys- 

 tals of salt exposed to moist air for a little time show de- 

 pressions which liave the form of a four-sided pyramid. 

 Hydrofluoric acid, also, will in a few moments produce dis- 

 tinct though microscopic etchings on a thin plate of ordinary 

 potash-mica, while a corresponding result is obtained by 

 treating crystals of garnets with caustic alkalies. The in- 

 terest of these and similar experiments is that they give 

 us an insight, as nothing else can, into the molecular struct- 

 ture of the crystals, or, in other words, the way they have 

 been built up. Some authors have even maintained that 

 the form of the etchings produced must be that of the 

 fundamental molecules, and, though this may not be sus- 

 tained, the relation that subsists must certainly be a close 

 one. 



MINERAL STATISTICS OF THE COLONY OF YICTORIA. 



From a report upon the mineral statistics of the colony of 

 Victoria for the year 1874, which has lately been presented 

 to Parliament, we glean the following facts : The amount of 

 gold raised in the colony in 1871 was 1,290,844 ounces; in 

 1872, 1,218,094 ounces; in 1873, 1,162,492 ounces; and in 

 1874, 1,105,115 ounces. The value of the machinery and ap- 

 pliances used on the gold-fields in 1874 was 2,078,936 (or 

 something over $10,000,000), the total area of the auriferous 

 district worked upon was 1063 square miles, and the number 

 of distinct quartz reefs was 3398. One hundred and eighty 

 tons of silver ore were raised during the year, from which 

 11,906 ounces of silver were extracted. 



DAUBREITE. 



The new m'mevsil Daiibi^eite, from the bismuth mine of Cer- 

 ro de Tazna,in Bolivia, has lately been described by Domey- 

 ko. It occurs in yellowish or grayish earthy masses, in 

 which occur many crystalline lamellae of a pearly lustre, and 

 opaque. Specific gravity about 6.5. In composition it is 

 an oxychloride of bismuth. 6 , April, 1876, 922. 



